[view_curses] fix for attr ranges that cover tabs

src/view_curses.cc

@@ -150,13 +150,18 @@ void view_curses::mvwattrline(WINDOW *window,
 
         tab_iter = tab_list.lower_bound(attr_range.lr_start);
         if (tab_iter != tab_list.end()) {
-            attr_range.lr_start += (tab_iter->second - tab_iter->first) - 1;
+            if (attr_range.lr_start > tab_iter->first) {
+                attr_range.lr_start += (tab_iter->second - tab_iter->first) - 1;
+            }
         }
 
         if (attr_range.lr_end != -1) {
             tab_iter = tab_list.lower_bound(attr_range.lr_end);
             if (tab_iter != tab_list.end()) {
-                attr_range.lr_end += (tab_iter->second - tab_iter->first) - 1;
+                if (attr_range.lr_end > tab_iter->first) {
+                    attr_range.lr_end += (
+                        tab_iter->second - tab_iter->first) - 1;
+                }
             }
         }